1. Field of the Invention
The invention generally relates to the field of fuel additive compositions and particularly to fuel additive compositions capable of increasing the thermal efficiency of internal combustion engines, thereby to increase fuel economy.
2. Description of the Prior Art
Fuel additives have long been employed to provide a variety of functions in fuels intended for consumption in internal combustion engines, these functions ranging from cleaning to anti-icing and from anti-knock to bacterial growth inhibition. Such additives, which may either be introduced at the refinery or directly into a fuel tank essentially at the use site, have little effect on the thermal efficiency of an engine, a not so surprising situation since the heat value of a fuel cannot reasonably be expected to increase due to the introduction of an additive which is present in a concentration of only a few percent. While certain additives available on the market promise fuel economy, it has not been shown that substantial economies are realized through the use of the presently available additives. Exhaustive testing has shown that the average thermal efficiency of present internal combustion engines seldom exceeds 10% and varies little when fuel additives are present in the fuel. An unfortunate but unavoidable fact thus presents itself, that is, the average internal combustion engine such as in use in the average vehicle must burn nearly 10 gallons of fuel in order to extract the work equivalent actually present in only one gallon of fuel. The work equivalent in nearly nine gallons of fuel is simply lost or "wasted" in the conversion process, a waste which not only directly contaminates the environment, but which also increases its entropy.
While pollution control measures have come into use in automotive vehicles by legislative demand, such measures require the burning of even greater quantities of fuel in order to reduce environmental pollution. Recent fuel efficiency increases which accompanied these pollution control measures have not been due to improvements in combustion efficiency, but to reductions in the weight of vehicles. Specific fuel consumption, thus fuel economy, is improved with increases in compression ratio; however, present automotive engines must be operated at relatively low compression ratios and also must drive the devices which effect pollution control, thus further decreasing fuel economy.
Additives such as are described by Coffield in U.S. Pat. No. 3,318,812 are primarily intended to reduce emissions in internal combustion engines, those fuel additives described by Rosenwald in U.S. Pat. No. 3,756,795 actively reduce icing while Niebylski et al in U.S. Pat. No. 4,005,992 provide anti-knock fuel additives. The additives referred to above, as well as the anti-bacterial fuel additives of Cadorette et al disclosed in U.S. Pat. No. 3,719,458 are comprised of alcohols or amines, the compositions having no affect on the combustion efficiency of an engine.
The present fuel additives specifically intend to increase thermal efficiency by improving the combustion characteristics of an engine in which a given fuel is burned. The present additives improve fuel vaporization and distribution as well as post-combustion conditions in the engine, thereby providing improvements in the combustion process itself and thus the fuel economy in the engine.